Haaretz described the document as a "non-paper ... that is not signed and lacks legal standing - its nature is political."

According to Geoffrey Aronson, an American from the Washington-base d Foundation for Middle East Peace, who was involved in the talks, an agreement under American auspices would call for Syria to ensure that Hezbollah would limit itself to being solely a political party.

He also told Haaretz that Khaled Meshal, Hamas' political bureau chief, based in Damascus, would have to leave the Syrian capital.

Syria would also exercise its influence for a solution to the conflict in Iraq, through an agreement between Shi'a leader Muqtada Sadr and the Sunni leadership, and in addition, it would contribute to resolving the Israeli-Palestinian conflict, including the refugee problem.

• As part of the agreement on principles, Israel will withdraw from the Golan Heights to the lines of 4 June, 1967. The timetable for the withdrawal remained open: Syria demanded the pullout be carried out over a five-year period, while Israel asked for the withdrawal to be spread out over 15 years.

• At the buffer zone, along Lake Kinneret, a park will be set up for joint use by Israelis and Syrians. The park will cover a significant portion of the Golan Heights. Israelis will be free to access the park and their presence will not be dependent on Syrian approval.

• Israel will retain control over the use of the waters of the Jordan River and Lake Kinneret.

• The border area will be demilitarized along a 1:4 ratio (in terms of territory) in Israel's favor.

• According to the terms, Syria will also agree to end its support for Hezbollah and Hamas and will distance itself from Iran.

Dov Weisglass, Mr Sharon's former chief of staff, said: "It is very possible that a group of people met, negotiated and formulated a document.

"But, during Sharon's term as prime minister, did the Prime Minister's Office have an officially approved agreement on this or any other similar procedure? The answer is 'no'."

A spokesman in Prime Minister Ehud Olmert's office also said that the Israeli government was unaware of any such meetings. But The Associated Press reports that another Israeli government official, speaking on condition of anonymity, confirmed that the talks had taken place but were not officially sanctioned.

Haaretz reports that the Syrian government has also denied that the talks took place. "No negotiations took place, the Haaretz report is completely false," a Syrian Foreign Ministry official said in Damascus.

The BBC reports, however, that Dr. Alon Liel, one of the Israeli negotiators, also confirmed that the secret talks were held, but said that they had been arranged in a private capacity and were not officially sanctioned by Israel. The talks apparently collapsed with Israel's war in Lebanon last summer. Haaretz reported that Dr. Liel also said "meetings on an unofficial level have been a fairly common phenomenon during the past decade."